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shorted sammichSID -please help


rbv2

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hi all,

 

build my sammichSID 3 years ago with no problems. now i got it back from a friend and the backlight of the display was not working anymore.

i tried to find out whats wrong and found the display backlight is working when powered from a battery.

 

during testing with an led on pins B-/B+ i somehow shorted the little sammichSID. when i turn on the unit all i can see now is the row of black boxes on the screen like without firmware.

it is still doing the start sound and the flashing led sequence in the beginning. I tried to re-upload the firmware but nothing changed.

 

what else can i try? please help.

 

thanks

 

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You might've fried your LCD, that's easy to do. You describe shorting the backlight, well if you've applied a high current across any of the data lines that could knock out some of the circuitry. Do you have the option of using a second backlight for a test? If so, be sure you don't have any shorts that might repeat the process and outcome.

 
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thanks for your reply.

 

unfortunately its the only lcd i have. the lcd is working i guess because it looks like before i uploaded the sid application. black squares in the upper row.

is there another way to test the lcd?

how do i check the connections between lcd and pic?

 

thanks

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i did the lcd test. all pins show the correct voltage but the lcd doesnt change.. so is it broken like latigid on said?

 

after that i uploaded the mios 1.9g and sammich.hex again, application is up and running but .. still black squares :(

 

is it time to buy new lcd?

 

thanks sneakthief regards from leipzig :)

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thank you hawkeye!

 

but i still have no clue why the backlight was not working (before shorted).. because all the voltage seems to be correct and the backlight lights up when powered from external battery..

 

found this on ebay:

http://www.ebay.de/itm/DISPLAYTECH-202A-BA-BC-LCD-532-6571-/321314061515?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item4acfcf7ccb

 

does it work as replacement or is there any difference regarding the pins?

Edited by rbv2
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It is probably fried - but before you replace it, give the contrast pot a try... Solid black boxes sometimes are caused by wrong LCD contrast. But I fear the short sent it to LCD nirvana :-)

 

Many greets,

Peter

unfortunately its not the contrast..

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